Bernoulli distribution

Toss a coin, how likely it lands on heads (1) or tails (0)?

$p$
$$ p(k)= \begin{cases} p, & \text{if $k=1$,} \\ 1-p, & \text{if $k=0$,} \\ 0, & \text{otherwise.} \end{cases} \\[20pt] \text{where $p$ is the probability the coin lands on heads.} $$